With the advancement of science and technologies, use of mobile apparatuses such as smartphones and tablet computers has become increasingly widespread. Because built-in memories of such mobile apparatuses have a limited capacity and are difficult to be extended, portable data transmitting devices that can be externally attached to such mobile apparatuses have been developed to additionally provide a sufficient storage capacity for the user. Moreover, this kind of portable data transmitting devices can also be connected to computers or other electronic products.
However, when being connected to a mobile apparatus, such a portable data transmitting device usually protrudes and suspends from an interface located on a bottom surface of the mobile apparatus. This causes inconveniences in use of the portable data transmitting device (i.e., the user shall pay special attention to prevent the portable data transmitting device from being knocked by other objects), and the protruding portable data transmitting device is liable to wobbling or being bent that would cause damage to the connector of the portable data transmitting device or even to the interface of the mobile apparatus.
In view of this concern, an L-shaped portable data transmission device has been proposed in the industry. That is, when the portable data transmitting device is connected to the mobile apparatus, a body of the portable data transmitting device is located on a back cover of the mobile apparatus to reduce the protruding extent. However, the distance between the connector and the body of such a portable data transmitting device is invariable, so the portable data transmitting device cannot be used for mobile apparatuses of different thicknesses. In other words, in case of a mobile apparatus having a relatively small thickness, the body of the portable data transmitting device is unable to abut on the back cover of the mobile apparatus but, rather, suspends from above the back cover, so there is still a possibility of wobbling or being bent; and in case of a mobile apparatus having a relatively large thickness, the connector of the portable data transmitting device is unable to be inserted into the interface of the mobile apparatus.
Accordingly, how to make improvement on the aforesaid shortcomings is still a problem to be solved in the art.